Filter Thread Lubrication?

Search didn't help me. I am wondering about lubricating filter threads. Anodizing the aluminum filter rings coats them with aluminum oxide. No wonder they are scratchy and prone to jamming, as aluminum oxide is also one of the most commonly-used abrasives. Not what you would normally order up as a surface finish for fine threads cut in soft metal.

Trouble is, anything I can think of to lubricate has potentially evil side effects. Oil on the lens? No. Graphite particles on the lens? No. Dry lubricant flakes on the lens? No. Maybe a wax like beeswax? I dunno.

Any experience out there? (Spare me the theories and uninformed guesses, please.)

Anodizing is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts.(1)

If the thread are scratchy, it's because they are cheap filters with poor machining. If you're not going to get expensive filters, get the less expensive ones with rings made of plastic; they'll be smoother.

.... I've never had a problem with filter threads (I use B+W filters which have brass rings) but I do disassemble all my pol. filters and hand lap them with lapping compound. They are smooth as butter. I would think that would work on the threads as well. Try jewelers rouge. ...... I wouldn't think of using plastic filters. .....

You don't need to tighten filters onto the lens. You just need to screw them on and leave them loose. Just enough so they don't fall off. The only filters you should tighten on are the ones you intend on leaving on semi-permanently (let's not start yet another debate on filter vs no-filter please).

Try not to squeeze the filter ring to grip it. The ring flexes under the pressure ever so slightly which binds the threads.

The tolerances of the filter threads are pretty loose. If they bind easily (cheap filter?), check the threads for damage. Probably previously cross threaded and forced.

Never had a problem. Never needed lubrication and its probably a bad idea. Using quality filters.

You shouldn't need to lubricate the threads, if they are correctly made then cleanliness is the best lubrication. At most a rub from a 4B pencil will be all you need. Make sure all the threads are clean will be a much better option.

... I use B+W filters which have brass rings ... hand lap them with lapping compound. They are smooth as butter. I would think that would work on the threads as well. Try jewelers rouge ...

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Hmmm... I generally buy good brand name filters but have not bought B&W. Brass is clearly a better material than aluminum for filter rings, though. As it happens I just ordered a B&W filter for my new Panny Mk II 14-140mm so I will take a hard look it.

Re lapping, good suggestion. I'm not sure how it would work with anodized aluminum though as aluminum oxide is pretty hard; probably I would have to find silicon carbide or diamond compounds. I think the rouge I have is garnet -- very soft. I'll first try Barry's suggestion of using moly. I have some very nice moly sear grease but I see that Brownells also sells a dry film lube that is pure moly in a solvent. I'll try a jar of that -- much easier that lapping!.

Search didn't help me. I am wondering about lubricating filter threads. Anodizing the aluminum filter rings coats them with aluminum oxide. No wonder they are scratchy and prone to jamming, as aluminum oxide is also one of the most commonly-used abrasives. Not what you would normally order up as a surface finish for fine threads cut in soft metal.

Trouble is, anything I can think of to lubricate has potentially evil side effects. Oil on the lens? No. Graphite particles on the lens? No. Dry lubricant flakes on the lens? No. Maybe a wax like beeswax? I dunno.

Any experience out there? (Spare me the theories and uninformed guesses, please.)

Click to expand...

I've been using B+W filters for many years and they are all brass and have never given me a problem. I have had some problems using B+W step up filter adapters. I have various sized front threads on my lenses and use step up rings to mount the larger filters on many smaller lenses. The B+W filters work well with the step up filter adapters because their threads are brass even though the B+W filter adapters are aluminum threads. However I've have some binding issues when mounting the filter adapters to other aluminum lens accessories such as extension tubes. I try not to tighten them up but they still bind up. I'm switching to Heliopan filter adapters which are all brass threads and never bind up with any aluminum accessory.
Thanks to all who posted some excellent ideas to prevent/resolve this binding issue!

I think that will work just fine. Bottle came today and I have already tried it. Step-up/down rings thread more smoothly onto filters, no more "slight scraping sound." As advertised, the moly ends up as a smooth film that doesn't look like it can flake. I did have some trouble finding pure moly in solvent; several vendors also include graphite -- which I don't want.

For those who are interested, what I am using is "Sentry Solutions Smooth-Kote Gun Lube." It is a thin black liquid that you just paint onto degreased metal. It dries quickly and leaves a dark silver-grey film. It air dries very quickly and according to the bottle, cures at room temperature in a couple of hours. Internet wisdom indicates that it can be dissolved with common solvents before curing, not so much afterwards.